The Johns Hopkins Precursors Study is one of the longest continuously functioning prospective studies in existence. Data collection began in 1947, and the study is about to enter its 50th year of follow-up. Its core is the study of aging - 1,337 former medical students in the classes of 1948-64 have been followed from age 22 to 67 years, with high response rates. This cohort is homogenous in having high levels of education, socioeconomic status, and access to health care -- factors that strongly affect most health outcomes, so it provides relatively unconfounded and precise estimates of risk associated with factors assessed repeatedly over the life course. The investigators note that work over the last project period has documented the relation of characteristics assessed in youth and midlife to disease in midlife and the low incidence of functional limitations in this cohort. The next 5 years provide a crucial window of opportunity in the life of this group to accomplish the following specific aims: 1) to continue the detailed description of the onset of disease and death in a standardized fashion in this ongoing longitudinal cohort study; 2) to determine risk of disease and death associated with alcohol intake, physical inactivity and other factors, over the life course from young adulthood to old age; 3) to determine the relation of psychologic, social, and health behavioral factors and disease assessed at multiple times from youth to middle age to onset of mild functional difficulty and use of compensatory responses to preserve physical function; in addition, the relationship of use of compensatory mechanisms to the subsequent trajectory of decline in physical function will be determined; and 4) to examine determinants of end-of-life planning, attitudes toward aggressive care, and end-of-life care that are consistent with previously expressed wishes of the study participants. The investigators state that the results of the proposed work will set the stage for preventive interventions to prevent disease and loss of physical function in older persons as well as to improve end-of-life planning.